[SOLVED] How Can we create a topic in Kafka from the IDE using API - kafka

[SOLVED] How to Create a Kafka Topic from Your IDE Using the API

In this chapter, we will learn how to create a Kafka topic from your IDE using the Kafka API. Kafka topics are very important for how data is organized and used in Kafka. So, it is necessary for us to know how to manage them using code. We will give you a simple step-by-step guide. This guide will help you set up your Kafka environment, add the required dependencies to your IDE, configure producer settings, and write the code to create a Kafka topic. By the end, you will know how to create Kafka topics easily.

In This Chapter, We Will Discuss:

Setting Up Your Kafka Environment: Make sure you have a working Kafka setup.
Adding Kafka Dependencies to Your IDE: Add Kafka libraries to your project.
Configuring Kafka Producer Properties: Learn how to set up properties for your Kafka producer.
Writing the Code to Create a Kafka Topic: Code examples will help us create a topic using code.
Executing the Topic Creation Code: Run the code to create the topic in Kafka.
Verifying the Topic Creation in Kafka: Check if your topic is created successfully.

For more details about Kafka topics, you can check our guide on how to create topic in Kafka. If you do not know much about Kafka or want to refresh your memory about its structure, visit our Kafka introduction page for more information.

By following these steps, we will be ready to work in the Kafka ecosystem and use its strong features.

Part 1 - Setting Up Your Kafka Environment

To create a Kafka topic from our IDE using the Kafka API, we need to set up our Kafka environment. First, we must make sure that Apache Kafka is installed and running on our local machine or server. Let us follow the steps below to set up our Kafka environment.

Install Apache Kafka: If we have not installed Kafka yet, we can download it from the official Kafka website. After download, we extract the files to a folder we like.
Install Zookeeper: Kafka needs Zookeeper to manage brokers. Kafka has a built-in Zookeeper we can use for development.
Start Zookeeper: We open our terminal or command prompt. Then we go to our Kafka folder and run this command to start Zookeeper:
```
bin/zookeeper-server-start.sh config/zookeeper.properties
```
(On Windows, we use bin\windows\zookeeper-server-start.bat config\zookeeper.properties.)
Start Kafka Server: In a new terminal window, we start the Kafka broker by running this command:
```
bin/kafka-server-start.sh config/server.properties
```
(On Windows, we use bin\windows\kafka-server-start.bat config\server.properties.)
Verify the Installation: After Zookeeper and Kafka are running, we check if our Kafka server is working. We can use this command to list the topics:
```
bin/kafka-topics.sh --list --bootstrap-server localhost:9092
```
(On Windows, we use bin\windows\kafka-topics.bat --list --bootstrap-server localhost:9092.)
Kafka Environment Variables: We may want to set up environment variables for easier access to Kafka commands. We can add the Kafka bin folder to our system’s PATH variable.

When we finish these steps, we will have a working Kafka environment ready for creating topics and other tasks. We should check that the logs for both Zookeeper and Kafka show no errors when they start.

For more details, we can look at how to install Kafka on Windows if we use Windows.

Part 2 - Adding Kafka Dependencies to Your IDE

To create a Kafka topic from our Integrated Development Environment (IDE) using the Kafka API, we first need to make sure we have the right Kafka dependencies in our project. This part can change based on the build tool we are using like Maven or Gradle. We will show how to add Kafka dependencies for both Maven and Gradle.

Adding Kafka Dependencies with Maven

If we are using Maven, we must add the Kafka client library to our pom.xml file. Here is an example of how to add the needed Kafka dependencies:

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka-clients</artifactId>
    <version>3.5.0</version> <!-- Use the latest version -->
</dependency>

We should check the Maven Repository for the latest version of the Kafka clients.

Adding Kafka Dependencies with Gradle

If we are using Gradle, we need to add this line to our build.gradle file under dependencies:

implementation 'org.apache.kafka:kafka-clients:3.5.0' // Use the latest version

Additional Dependencies

Depending on what we need for our application, we might also need to add other dependencies like logging (Log4j or SLF4J) or testing (JUnit). Here’s how to add SLF4J for logging in Maven:

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.32</version>
</dependency>

And in Gradle:

implementation 'org.slf4j:slf4j-api:1.7.32'

IDE Configuration

After we add the dependencies, we need to make sure our IDE sees them. In IntelliJ IDEA, we may need to refresh our Maven or Gradle project to download and index the new libraries. In Eclipse, we can right-click our project and choose Maven > Update Project or Gradle > Refresh Gradle Project.

By doing these steps, we can include the necessary Kafka dependencies in our IDE easily. This setup is important for creating a Kafka topic using the Kafka API in the next steps.

For more details about creating a Kafka topic, we can look at this guide.

Part 3 - Configuring Kafka Producer Properties

To create a Kafka topic and send messages from your IDE using the Kafka API, we need to set up the properties for the Kafka producer. These properties tell the producer how to act and connect to the Kafka cluster. Here are the main settings we need for our Kafka producer.

1. Necessary Producer Properties

We usually configure the following properties for our Kafka producer:

bootstrap.servers: This is a list of host and port pairs. The producer uses this to connect to the Kafka cluster. For example:
```
bootstrap.servers=localhost:9092
```
key.serializer: This property defines the class that will convert the key of the messages we send. If we send string keys, we use:
```
key.serializer=org.apache.kafka.common.serialization.StringSerializer
```
value.serializer: Like the key serializer, this defines the class for the value of the messages. For string values, we would use:
```
value.serializer=org.apache.kafka.common.serialization.StringSerializer
```
acks: This property tells us how the producer will wait for an acknowledgment. We can set it to:
- 0: The producer does not wait for acknowledgment.
- 1: The producer gets acknowledgment after the leader replica gets the data.
- all: The producer waits for all in-sync replicas to confirm receipt of the data.
For example, to make sure our data is safe, we can set:
```
acks=all
```
retries: This property lets the producer try to send messages again if there are temporary problems. We should set this to a positive number for better reliability:
```
retries=3
```

2. Example Configuration Code

Here is how we can set these properties in our Java code:

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.StringSerializer;

import java.util.Properties;

public class KafkaProducerConfig {

    public static KafkaProducer<String, String> createProducer() {
        Properties properties = new Properties();
        properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        properties.put(ProducerConfig.ACKS_CONFIG, "all");
        properties.put(ProducerConfig.RETRIES_CONFIG, 3);

        return new KafkaProducer<>(properties);
    }
}

3. Additional Configuration Options

Besides the basic settings, we may want to think about these extra options to make our producer better:

linger.ms: This property controls how long to wait before sending a batch of messages. A bigger number can help with speed but may slow down response time.
```
linger.ms=5
```
batch.size: This is the maximum size for a batch of records sent to the broker. Making this bigger can help with sending lots of messages at once.
```
batch.size=16384
```
compression.type: Use this to set the type of compression for message values. Options include gzip, snappy, or lz4:
```
compression.type=gzip
```

By setting these producer properties right, we make sure our Kafka producer can talk well with the Kafka cluster and handle messages easily. For more details about Kafka configurations, we can check this resource.

Following these tips will help us for the next steps in creating a Kafka topic and sending messages to it.

Part 4 - Writing the Code to Create a Kafka Topic

To create a Kafka topic with code, we can use the Kafka AdminClient API. This API helps us with tasks like creating, deleting, and describing topics. Here is a simple guide on how we can write the code to create a Kafka topic.

Step 1: Import Required Libraries

First, we need to add the necessary Kafka libraries to our project. If we are using Maven, we can add this dependency in the pom.xml file:

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka-clients</artifactId>
    <version>3.4.0</version> <!-- Check for the latest version -->
</dependency>

Step 2: Configure the Admin Client

Next, we must set up the AdminClient with the settings needed to connect to our Kafka cluster. Here is a sample setup:

import org.apache.kafka.clients.admin.AdminClient;
import org.apache.kafka.clients.admin.NewTopic;

import java.util.Collections;
import java.util.Properties;

public class KafkaTopicCreator {

    private static AdminClient createAdminClient(String bootstrapServers) {
        Properties properties = new Properties();
        properties.put("bootstrap.servers", bootstrapServers);
        properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        return AdminClient.create(properties);
    }
}

Step 3: Write the Code to Create the Topic

Now we can create a new topic by giving it a name, the number of partitions, and the replication factor. Here is how we do that:

public void createTopic(String topicName, int partitions, short replicationFactor) {
    AdminClient adminClient = createAdminClient("localhost:9092"); // Change this to your bootstrap server

    NewTopic newTopic = new NewTopic(topicName, partitions, replicationFactor);

    try {
        adminClient.createTopics(Collections.singleton(newTopic)).all().get();
        System.out.println("Topic created successfully: " + topicName);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        adminClient.close();
    }
}

Example Usage

We can call the createTopic method to make a new Kafka topic. Here is a simple example of how we can use the KafkaTopicCreator class:

public static void main(String[] args) {
    KafkaTopicCreator topicCreator = new KafkaTopicCreator();
    topicCreator.createTopic("my-new-topic", 3, (short) 1);
}

Explanation

AdminClient: This class helps us to work with the Kafka cluster for admin tasks.
NewTopic: This class is for creating a new topic. It needs the topic name, number of partitions, and replication factor.
createTopics(): This method creates the topic in the Kafka cluster. We call this method inside a try-catch block to catch any errors that may happen when creating the topic.

Additional Resources

For more information about setting up Kafka topics, check the official documentation on how to create a topic in Kafka.

Part 5 - Running the Topic Creation Code

To run the code that makes a topic in Kafka, we need to make sure that our Kafka server is running. If we haven’t set it up yet, we can check the guide on how to install Kafka on Windows for help.

Steps to Run the Topic Creation Code

Start the Kafka Server: We need to make sure that both ZooKeeper and Kafka broker services are running. We can start them using the command line:
```
zookeeper-server-start.bat config/zookeeper.properties
kafka-server-start.bat config/server.properties
```
Run Our Java Program: If we wrote our Java code to create a topic as we talked in Part 4, we need to run this program. We have to make sure our IDE is set up right and that we included the Kafka dependencies in our project.

Example Java Code Running: Here is a sample Java class that we might have made to create a Kafka topic. We need to compile and run this in our IDE:

import org.apache.kafka.clients.admin.AdminClient;
import org.apache.kafka.clients.admin.NewTopic;

import java.util.Collections;
import java.util.Properties;

public class KafkaTopicCreator {

    public static void main(String[] args) {
        Properties properties = new Properties();
        properties.put("bootstrap.servers", "localhost:9092");
        try (AdminClient adminClient = AdminClient.create(properties)) {
            NewTopic newTopic = new NewTopic("my_new_topic", 1, (short) 1);
            adminClient.createTopics(Collections.singleton(newTopic));
            System.out.println("Topic created successfully!");
        } catch (Exception e) {
            System.err.println("Failed to create topic: " + e.getMessage());
        }
    }
}

Compile and Run: In our IDE, we need to compile the Java file and run it. We should see a message that says the topic has been created successfully.
Error Handling: If we get any errors while running, we should check the Kafka server logs for more information. Some common problems are:
- Kafka not running
- Wrong configuration properties
- Network problems
Check Topic Creation: After we run the program, we can check if the topic is created using the Kafka command-line tool:
```
kafka-topics.bat --list --bootstrap-server localhost:9092
```
This command will show us all the topics, including the one we just made.

By doing these steps, we can run our Kafka topic creation code successfully. For more advanced Kafka settings and properties, we can look at Kafka topics.

Part 6 - Verifying the Topic Creation in Kafka

After we create a Kafka topic using our IDE and the Kafka API, we need to check that the topic is made correctly. There are a few ways to do this. We can use command-line tools, the Kafka AdminClient API, or a Kafka management tool.

Method 1: Using Kafka Command-Line Tools

Kafka has a command-line tool that helps us list the topics in our Kafka cluster. We can run this command to check the topic creation:

# Go to the Kafka installation folder
cd /path/to/kafka/bin

# List all topics
./kafka-topics.sh --list --bootstrap-server localhost:9092

We should change localhost:9092 to our Kafka broker address. This command shows all topics in our Kafka cluster. We should see our new topic in the list.

Method 2: Using Kafka AdminClient API

If we want to check the topic with code, we can use the AdminClient class in the Kafka API. Here is a simple Java code example that shows how to check if a topic exists:

import org.apache.kafka.clients.admin.AdminClient;
import org.apache.kafka.clients.admin.ListTopicsResult;
import org.apache.kafka.clients.admin.TopicDescription;
import org.apache.kafka.clients.admin.AdminClientConfig;
import java.util.Properties;
import java.util.Set;

public class VerifyKafkaTopic {
    public static void main(String[] args) {
        Properties properties = new Properties();
        properties.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        AdminClient adminClient = AdminClient.create(properties);

        try {
            ListTopicsResult topicsResult = adminClient.listTopics();
            Set<String> topicNames = topicsResult.names().get();

            String topicToVerify = "your_topic_name"; // change this to your topic name
            if (topicNames.contains(topicToVerify)) {
                System.out.println("Topic " + topicToVerify + " exists.");
            } else {
                System.out.println("Topic " + topicToVerify + " does not exist.");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            adminClient.close();
        }
    }
}

Method 3: Using Kafka Management Tools

If we are using a Kafka management tool like Confluent Control Center, Kafka Manager, or Kafdrop, we can easily check the topic creation:

Confluent Control Center: Go to the Topics page. Here we can see all topics and their settings.
Kafka Manager: This tool gives a friendly view to see all topics, their partitions, and their status.
Kafdrop: Open the Kafdrop UI and go to the Topics section to see details about our topic.

Summary

We must verify the topic creation in Kafka after we make a Kafka topic using the API. We can use command-line tools, AdminClient API, or management tools to check if our topic is created and working well. For more details on how to create topics, we can look at this guide on how to create a topic in Kafka.

Conclusion

In this article, we looked at how to make a Kafka topic from our IDE using the Kafka API. We talked about important steps. First, we need to set up our Kafka environment. Then, we add dependencies. After that, we configure the producer properties. Finally, we run the code to create the topic.

This guide makes the process easier. It also helps us understand Kafka better. For more information, we can check out our full guide on how to create a topic in Kafka. We can also learn about Kafka’s basic operations.

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